Increased Expression of Proliferating Cell Nuclear Antigen mRNA in Peripheral Blood Mononuclear Cells from Patients with IgA Nephropathy

Abstract

Proliferating cell nuclear antigen (PCNA)/cyclin is an intranuclear polypeptide antigen whose appearance correlates with the proliferative state of cells. The authors investigated the expression of PCNA from peripheral blood mononuclear cells (PBMC) in 23 patients with IgA nephropathy and 10 healthy age-matched controls, using ribonucleic acid hybridization techniques. The majority of patients with IgA nephropathy (22 of 23 patients) showed elevated PCNA expression in PBMC, while no PCNA expression was detected in PBMC of normal controls. A positive correlation was noted between PCNA expression of PBMC and glomerular injuries and PCNA expression and urinary protein excretion. Sixty-three percent of patients with grade III and IV histological findings showed strong PCNA (more than ) expression in their PBMC. The urinary protein excretion in patients who showed more than ( ) PCNA expression was more than 2.5 g/d, while that in patients with less than (+) PCNA expression was less than 1.0 g/day. These findings indicate that abnormally regulated PCNA expression in PBMC may play an important role in the progression of IgA nephropathy, and that PCNA expression in PBMC may be a useful indicator of disease activity.